The purpose of jQuery is to make it much easier to use JavaScript on your website.

What is jQuery?

jQuery is a lightweight, "write less, do more", JavaScript library.The purpose of jQuery is to make it much easier to use JavaScript on your website.jQuery takes a lot of common tasks that requires many lines of JavaScript code to accomplish, and wraps it into methods that you can call with a single line of code.jQuery also simplifies a lot of the complicated things from JavaScript, like AJAX calls and DOM manipulation.The jQuery library contains the following features:

HTML/DOM manipulation

CSS manipulation

HTML event methods

Effects and animations

AJAX

Utilities

Tip: In addition, jQuery has plugins for almost any task out there.

Why jQuery?

There are a lots of other JavaScript frameworks out there, but jQuery seems to be the most popular, and also the most extendable.Many of the biggest companies on the Web use jQuery, like:

Google

Microsoft

IBM

Netflix

Query is very strong tool. The same functionality implemented in JavaScript can be implemented very efficiently in J query.

Click here to see J Query effective sample and comparison with JavaScript.